Could a logical network be a data-security attribute?

Telstra Gateway Frontier modem router press picture courtesy of Telstra

The local network created by one of these routers could be seen as a way to attest proximity or effective control of these devices

In data security, there has to be a way to attest that a user has effective control of their computing devices when they are authenticating with a device or service. Increasingly, most of us are handling two or more devices in this context such as to move data between them, use one of them as an authentication factor or to verify mutual trust between two or more people.

The logical network, also called a subnet, represents the devices connected to the same router irrespective of what media they use to connect to this network like Ethernet or Wi-Fi wireless. It is represented at Layer 3 (Network Layer) on the OSI network model stack and is represented by IP (Internet Protocol) whether version 4 or 6. Routers that implement guest or hotspot/community network functionality create a separate logical network for the guest or hotspot network.

But a hotspot network can be set up to cover a large public area like a bar or cafe’s dining room or even the whole of a hotel or apartment block. As well, if a hotspot network is properly set up for the end users’ data security, it shouldn’t be feasible to discover other devices on that same logical network. This is thanks to IP-based isolation functionality that the router that serves the hotspot offers.

Here, the existence of devices on the same logical network can be used as a way to attest proximity of these devices or to attest effective control over them.

Use cases

Enhanced two-factor authentication

Increasingly, most of us who implement two-factor authentication use an app on a smartphone to provide the random key number that confirms what we have along with what we know. But in a lot of situations, we have the smartphone and the computer we want to use to gain access to the resources existing on the same network. This may be our home or business network, a public-access hotspot or tethering our laptop to a smartphone for Internet access via the mobile network.

Having both devices on the same network could be seen as a way to assess the security level of a multifactor authentication setup by assessing the proximity of the devices to each other. It is more so if the devices are communicating to each other behind the same Wi-Fi access point or Ethernet switch. This concept would be to prove that both devices are effectively being controlled by the same user.

It can also work as an alternative to Bluetooth or NFC as a device-to-device link for a transcription-free multi-factor authentication setup if you are thinking of two devices that are able to connect to a network via Wi-Fi. This is more so where the issue of phishing of multi-factor authentication setups involving the transcription of a one-time passcode has been raised.

Discovery of devices in the same network

The same concept can also be examined in the context of interlinking between devices that exist on the same network or even determining one’s “home” domain in the context of AV content rights. In some ways, the concept could also be about tokenised login for online services where a user’s credentials are held on one device like a smartphone but a session-based token is passed to another device like a set-top box to facilitate login from that device.

It is a practice that has been used with UPnP and Bonjour technologies primarily for device and content discovery. The most obvious situation would be to use Apple AirPlay or Google Chromecast to throw content to the big screen from a compatible mobile device. It also works in the same context when you set up and use a network-based printer from your computer or smartphone.

Across-the-room discovery and mutual-user authentication

Another use case this concept can apply to is “across-the-room” device discovery and mutual-user authentication. This would be used for data transfer, social networks or online gaming where you intend to share a resource with someone you talked with, invite them as a friend / follower in a social network or engage them in an online game.

Proof of presence at a particular location

Use of a logical network’s attributes can be a tool for proving one’s presence at a particular location. This is more so where the Internet service for that network is being provided using a wired-broadband or fixed-wireless-broadband approach for its last-mile, like with most home and business networks. It may not work with “Mi-Fi” setups where a mobile broadband network is being implemented for the last-mile connection.

Here, it could be used for time-and-attendance purposes including “proof of presence” for home-based carers. Or it could be used to conditionally enable particular functionality like app-based on-premises food-and-beverage ordering at a venue. To the same extent, it could be used to protect delivery services against orders that were instigated at one location being sent to another location.

Methods

Both devices existing on the same network

In a premises-specific network like most small networks, testing that both devices are on the same subnet / logical network behind the same gateway device (router) could be a way to attest that both devices are in the same premises. The same test can be performed by the use of a “hop count” on Layer 3 of the OSI network-layer tree, which also determines the number of logical networks passed.

It is a method used with a wide range of network-based AV and printing applications to constrain the discovery and control of devices by controller software to what is local to you.

But assessing whether the two devices are connecting to the same access point on a Wi-Fi network can be used to attest whether both devices are in the same room in a large Wi-Fi setup. It may not work in a network setup where different devices connect to a network using different connection media like Ethernet, Wi-Fi Wireless or HomePlug powerline. This also includes situations where multiple access points cover the same room or floor such as with large rooms or open-plan areas.

Another approach that can be used for Wi-Fi hotspot networks honouring the Hotspot 2.0 / Passpoint setup would be to read the “venue” metadata for that network and compare whether both devices are in the same venue. If this technology is able to support subdividing of a logical venue such as based on floors or rooms, this could work as a way of further attesting whether both devices are in close proximity.

A Wi-Fi wireless network can be attested through the use of the BSSID which identifies the same access point that the devices are connecting through or the ESSID which is the network’s “call sign”. The BSSID could be used for a public hotspot network including a “hotzone” network ran by a local government or ISP,or a large network that uses many access points while the ESSID approach could be used simply for a small network with a few access points.

Trusted networks with authentication certificates

On the other hand, there could be the concept of creating “trusted networks” where authentication certificates relating to the network are stored in the network’s gateway device or in infrastructure devices associated with that network. It could be used to work against man-in-the-middle attacks as well as a stronger approach to attesting trust between the client device and the network it proposes to access.

The initial appeal for this concept could be to attest the authenticity of a business’s network especially in the face of business partners or customers who want to use that network as a gateway to the Internet or use the host business’s resources.

It could have some appeal to the food, beverage and hospitality industry where particular cafes and bars are often seen by individuals and workgroups as favoured hangouts. In this context, if an individual wants to use the Wi-Fi public-access network in their favourite “watering hole” or “second office”, the “trusted network” approach can be used to verify to the customer that they have connected to the venue’s network at the venue to avoid “man-in-the-middle” attacks.

This approach is being implemented with the Wi-Fi Passpoint / Hotspot 2.0 technology to provide for the simple yet secure public-access Wi-Fi network.

The same approach can be used with a home network if the router can store data like digital certificates in onboard non-volatile memory. Then this data could be created by the ISP as a “known trusted network” with a network-specific certificate relating to the router and network equipment. Such a service could be offered by an ISP as a value-added service especially to cater for “proof-of-presence” applications.

Conclusion

Using a logical network as a data-security attribute can be effective as a security tool for some use cases. With current network equipment, this can be a surefire way of assessing device proximity.to other devices. But use of certificates stored on network-infrastructure devices like routers and provided by ISPs or similar entities can be of use for authenticated-network or proof-of-presence applications.

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